Brookhaven Lab Chemist Shares the 2000 Wolf Prize
in Physics
With University of Tokyo Scientist For Research on Neutrinos

UPTON, NY - Raymond Davis Jr., whose career as a chemist spans
52 years at the U.S. Department of Energy's Brookhaven National
Laboratory, will share the 2000 Wolf Prize in Physics with Masatoshi
Koshiba, University of Tokyo, Japan. The Wolf Foundation has
recognized the scientists "for their pioneering observations
of astronomical phenomena by detection of neutrinos, which created
the emerging field of neutrino astronomy." The $100,000 prize,
to be shared by the two scientists, will be conferred by the President
of Israel, Ezer Weizman, at a special ceremony in Jerusalem on
May 21.

Davis was notified that he won the Wolf Prize while he was
in Russia to receive the 1999 Bruno Pontecorvo Prize. Issued
by the Joint Institute for Nuclear Research, the $1,000 Pontecorvo
Prize was awarded to Davis "for the outstanding achievement
in development of the chlorine-argon method for detection of solar
neutrinos." This method was invented by Pontecorvo and Davis
further developed it.

"I have been interested in studying neutrinos since 1948,
when I first read about them in a review article by H.R. Crane,
a physicist at the University of Michigan," Davis said. "Back
then, it was a brand new field of study. It has captivated me
for more than half a century."

Neutrinos, ghostlike particles that, until recently, have been
thought to have zero mass, are produced in the nuclear reactions
that provide the sun's energy. They rain down on each square
inch of the earth at the rate of 65 billion per second. Davis
first started investigating neutrinos that were produced in Brookhaven's
Graphite Research Reactor and in a reactor at the Savannah River
Technology Center in South Carolina in the 1950s. The particles
remained elusive until the 1960s, when Davis achieved success
in detecting solar neutrinos in a new experiment.

At the time, theorists believed that a solar neutrino produces
radioactive argon when it interacts with a nucleus of chlorine.
Davis developed an experiment based on this theory by placing
a 100,000-gallon tank of perchloroethylene - a chemical commonly
used by dry cleaners and a good source of chlorine - 4,800 feet
underground in the Homestake Gold Mine in South Dakota. The chlorine
target was located deep underground to protect it from cosmic
rays, and the target had to be very big because the probability
of capturing a neutrino in chlorine was ten quadrillion times
smaller than detecting it in a nuclear reactor.

Despite these odds, Davis's experiment confirmed that the sun
produces neutrinos, but only about one-third of the number of
neutrinos predicted by theory. This extraordinary finding gave
birth to a series of investigations by scientists around the world
that confirmed the solar neutrino deficit, with a maximum of 60
percent of the expected number ever detected. To this day, experiments
are ongoing to determine the cause of the deficit.

Wolf Prize co-recipient Masatoshi Koshiba led the design and
construction of the Kamiokande detectors in Japan, which recorded
the time of arrival, energy and direction of incoming neutrinos.
Experiments that used these attributes provided strong hints
that neutrinos have mass.

Raymond Davis Jr. earned a B.S. in 1937, and an M.S. in 1940,
from the University of Maryland, and a Ph.D. in physical chemistry
from Yale University in 1942. He served in the U.S. Air Force
from 1942-46, and, from 1946-48, he worked as a chemist at Monsanto
Chemical Company.

Davis started his career at Brookhaven Lab in 1948 as a scientist,
then was promoted to chemist in 1953, received tenure in 1956,
and became a senior chemist in 1964. He retired from Brookhaven
in 1984, and he then became a research professor at the University
of Pennsylvania. In addition, he has remained an active research
collaborator at Brookhaven Lab. A member of the National Academy
of Sciences, Davis has won numerous scientific awards, including
the Tom W. Bonner Prize in 1988 and the W.K.H. Panofsky Prize
in 1992.

The Wolf Foundation in Israel has awarded five Wolf Prizes
annually since 1978 to outstanding scientists and artists "for
achievements in the interest of mankind and friendly relations
among peoples, irrespective of nationality, race, color, religion,
sex, or political view." Davis will be the second honoree
from Brookhaven Lab; Maurice Goldhaber, Brookhaven's former director
and current distinguished scientist, shared the 1991 Wolf Prize
in Physics with Valentine L. Telegdi of the Swiss Institute of
Technology.

The U.S. Department of Energy's Brookhaven National Laboratory
creates and operates major facilities available to university,
industrial and government personnel for basic and applied research
in the physical, biomedical and environmental sciences, and in
selected energy technologies. The Laboratory is operated by Brookhaven
Science Associates, a not-for-profit research management company,
under contract with the U.S. Department of Energy.

NOTE TO LOCAL EDITORS: Raymond Davis is a resident of Blue
Point, N.Y..